The quiet power of the checklist

In 1935 a new bomber crashed because one very experienced pilot forgot one step. The fix was not a better pilot. It was an index card.

The aircraft was Boeing’s Model 299, the prototype that became the B-17. On 30 October 1935, at Wright Field in Ohio, it took off, climbed, stalled and crashed, killing two of the five crew. The cause was not a mechanical fault. The crew had left a gust lock engaged, a device that holds the control surfaces still on the ground. A reporter summed up the mood: this was “too much aeroplane for one man to fly”.

The card that saved the aeroplane

Boeing could have agreed and given up. Instead a group of test pilots did something modest and brilliant. They wrote a short checklist of the obvious: release the brakes, unlock the controls, close the doors and windows. Everything a competent pilot already knew, set down on a single card so it could not be left to memory on a busy morning. With the card in hand, the first aircraft went on to fly 1.8 million miles without a serious accident.

That is the part people miss. The checklist was never for the ignorant. It was for the expert, who knows all of it and will still, one day in a thousand, skip the step that is so routine it has become invisible.

Medicine had to learn it too

Decades later, surgery rediscovered the same idea. In 2009 a team led by Atul Gawande tested a simple 19-item surgical safety checklist across eight hospitals, from Tanzania to Toronto. The results were hard to argue with.

Outcome	Before checklist	After checklist
Surgical complications	11.0%	7.0%
In-hospital deaths	1.5%	0.8%

Source: Haynes et al, New England Journal of Medicine, 2009.

A card you could write in five minutes cut deaths and complications by roughly a third. It worked for the same reasons it worked at Boeing. It catches the step you skip precisely because it is routine. It gives quiet permission for a junior person to say “we have not done this yet”. And it spreads memory across the whole team, so no single tired person has to hold it all.

A checklist does not doubt your skill. It protects skilled people from a bad five minutes.

The art is in what you leave out

A good checklist is short. It covers the things that kill, not everything that could ever matter. Gawande draws a useful line between the read-do list, where you read a step and then do it, and the do-confirm list, where you work from memory and then pause to confirm the critical few. A list of ninety items gets ignored. A list of the six that matter gets used.

It is one of the most evidence-backed tools we have for doing careful work under pressure, and it costs almost nothing. There is something pleasing about that.

References

1. A. B. Haynes et al, “A Surgical Safety Checklist to Reduce Morbidity and Mortality in a Global Population”, New England Journal of Medicine, 2009. nejm.org.
2. Smithsonian National Air and Space Museum, “On. Set. Checked.” (history of the pre-flight checklist). airandspace.si.edu.
3. Flight Safety Australia, “One thing at a time: a brief history of the checklist”, 2018. flightsafetyaustralia.com.
4. Atul Gawande, The Checklist Manifesto (Metropolitan Books, 2009).

Shannon Hamming writes about how the working world keeps itself safe and honest: incident reporting, quality, ESG, compliance and the sensible use of technology in safety-critical work. Useful first, interesting always.